The present invention relates to illuminating pyrotechnic compositions, particularly those in signal or distress flares, and to signal flares and the like comprising such compositions. More specifically, the invention relates to a class of flare compositions known generally as non-metallic flare compositions, denoting the absence of particulate metals such as magnesium or aluminum from such compositions, and signal or distress flares comprising such compositions.
Signal or distress flares are generally known devices for providing illumination in the event of emergencies, such as the occurrence of an automobile accident or airplane or rail crash. Signal flares are also used by lost persons in order to attract searchers toward them, such as occurs in boating or hiking accidents occurring at night, or even during daylight hours. Signal flares may be also be used for a wide variety of other purposes, such as temporary illumination of a runway, or as part of fireworks displays.
Flare compositions may include brightly burning particulate metals, such as aluminum or magnesium powder, but the temperature of the combustion reaction of such metallic flare compositions is extremely high, thus increasing the risks of using such flares. In addition, metallic flare compositions burn much faster than non-metallic compositions, thus reducing their attractiveness where a sustained signal is desired. Metallic flare compositions also produce metallic ash, or "clinker," when burning, which then drops from the flare as it continues to burn, creating an unacceptable risk of causing fire in many applications where signal flares are most useful.
Cooler burning non-metallic flare compositions are generally known, having reduced risk of causing burns or fires caused by the flare itself, but flare brightness is reduced with respect to similarly sized flares comprising metallic compositions.
Thus there is a need for a brighter burning non-metallic flare composition in order to produce smaller flares without sacrificing brightness. Also, there is a need for brighter non-metallic flares of conventional size.